1 The present study evaluated the participation of tumour necrosis factor-a (TNF-a) in the inflammatory and nociceptive responses evoked by carrageenan in the mouse paw. 2 The intraplantar injection of carrageenan (300 mg paw À1 ) induced a marked and biphasic paw oedema formation (peaks at 6 and 72 h), which was accompanied by a long-lasting mechanical allodynia (that remained elevated for up to 72 h) and a significant increase of myeloperoxidase (MPO) activity (peak at 6 h) in both Swiss and C57/BL6 mice. 3 The paw oedema, the elevation of MPO activity and to a lesser extent the mechanical allodynia elicited by carrageenan were found to be significantly reduced in TNF-a p55 receptor knockout mice. 4 Of interest, the systemic administration of an anti-TNF-a antibody produced a significant inhibition of paw oedema, mechanical allodynia and MPO activity. A noteworthy decrease in inflammatory and nociceptive responses caused by carrageenan was also observed when mice were previously treated with the preferential inhibitor of TNF-a synthesis, thalidomide. 5 The present results clearly indicate that the proinflammatory cytokine TNF-a plays a critical role in the oedema formation, as well as in the mechanical allodynia and the neutrophil migration, following carrageenan administration into the mouse paw. Intraplantar injection of carrageenan in mice could constitute a useful model for assessment of the in vivo effects of potential inhibitors of TNF-a-related pathways.

Background and purpose: We investigated the mechanisms underlying the pruritogenic response induced by trypsin in mice, to assess the relevance of neurogenic inflammation components in this response. Experimental approach: Itching was induced by an intradermal injection of trypsin in the mouse neck. The animals were observed for 40 min and their scratching behaviour was quantified. Key results: Trypsin-induced itching was blocked by the lima bean trypsin inhibitor, the selective proteinase-activated receptor-2 (PAR-2) antagonist FSLLRY and PAR-2 receptor desensitization. An important involvement of mast cells was observed, as chronic pretreatment with the mast cell degranulator compound 48/80 or the mast cell stabilizer disodium cromoglycate prevented scratching. Also, trypsin response was inhibited by the selective COX-2 inhibitor celecoxib and by the selective kinin B 2 (FR173657) and B 1 (SSR240612) receptor antagonists. Moreover, an essential role for the mediators of neurogenic inflammation was established, as the selective NK 1 (FK888), NK 3 (SR142801) and calcitonin gene-related peptide (CGRP 8À37 fragment) receptor antagonists inhibited trypsin-induced itching. Similarly, blockade of transient receptor potential vanilloid 1 (TRPV1) receptors by the selective TRPV1 receptor antagonist SB366791, or by genetic deletion of TRPV1 receptor reduced this behaviour in mice. C-fibre desensitization showed a very similar result. Conclusions and implications: Trypsin intradermal injection proved to be a reproducible model for the study of itching and the involvement of PAR-2 receptors. Also, trypsin-induced itching seems to be widely dependent on neurogenic inflammation, with a role for TRPV1 receptors. In addition, several other mediators located in the sensory nerves and skin also seem to contribute to this process.

Background and Purpose: Intestinal mucositis refers to mucosal damage caused by cancer treatment, and irinotecan is one of the agents most associated with this condition. Focusing on the development of alternatives to prevent this important adverse effect, we evaluated the activity of the flavonoid luteolin, which has never been tested for this purpose despite its biological potential. Experimental Approach: The effects of luteolin were examined on irinotecaninduced intestinal mucositis in mice. Clinical signs were evaluated. Moreover, histological, oxidative, and inflammatory parameters were analysed, as well as the possible interference of luteolin in the anti-tumour activity of irinotecan. Key Results: Luteolin (30 mgÁkg −1 ; p.o. or i.p.) prevented irinotecan-induced intestinal damage by reducing weight loss and diarrhoea score and attenuating the shortening of the duodenum and colon. Histological analysis confirmed that luteolin (p.o.)prevented villous shortening, vacuolization, and apoptosis of cells and preserved mucin production in the duodenum and colon. Moreover, luteolin treatment mitigated irinotecan-induced oxidative stress, by reducing the levels of ROS and LOOH and augmenting endogenous antioxidants, and inflammation by decreasing MPO enzymic activity, TNF, IL-1β, and IL-6 levels and increasing IL-4 and IL-10. Disruption of the tight junctions ZO-1 and occludin was also prevented by luteolin treatment.Importantly, luteolin did not interfere with the anti-tumour activity of irinotecan. Conclusion and Implications: Luteolin prevents intestinal mucositis induced byirinotecan and therefore could be a potential adjunct in anti-tumour therapy to control this adverse effect, increasing treatment adherence and consequently the chances of cancer remission.

Taxane-derived drugs are antineoplastic agents used for the treatment of highly common malignancies. Paclitaxel and docetaxel are the most commonly used taxanes; however, other drugs and formulations have been used, such as cabazitaxel and nabpaclitaxel. Taxane treatment is associated with neurotoxicity, a well-known and relevant side effect, very prevalent amongst patients undergoing chemotherapy. Painful peripheral neuropathy is the most dose-limiting side effect of taxanes, affecting up to 97% of paclitaxel-treated patients. Central neurotoxicity is an emerging side effect of taxanes and it is characterized by cognitive impairment and encephalopathy. Besides impairing compliance to chemotherapy treatment, taxane-induced neurotoxicity (TIN) can adversely affect the patient's life quality on a long-term basis. Despite the clinical relevance, not many reviews have comprehensively addressed taxaneinduced neurotoxicity when they are used therapeutically. This article provides an up-to-date review on the pathophysiology of TIN and the novel potential therapies to prevent or treat this side effect. Abbreviations: Ca v , voltage-gated calcium; CB 1 , cannabinoid receptor 1; CB 2 , cannabinoid receptor 2; CCL2, chemokine (C-C motif) ligand 2; CCR2, CC motif chemokine receptor 2; CIPN, chemotherapy-induced peripheral neuropathy; CREB, cAMP response element-binding; CX3CL1, C-X3-C motif chemokine ligand 1; CXCL1, C-X3-C motif chemokine ligand 1; CXCL12, C-X-C motif chemokine ligand 12; CXCR1, C-X-C motif chemokine receptor 1; CXCR2, C-X-C motif chemokine receptor 2; DRG, dorsal root ganglion; GHS-R, growth hormone secretagogue receptor; IENFs, intra-epidermal nerve fibres; K ATP , ATP-sensitive potassium channel; K v , voltage-gated potassium channel; mPTP, mitochondrial permeability transition pore; Na v , voltage-gated sodium channel; Nrf2, nuclear factor-2 erythroid-related factor-2; PIPN, paclitaxel-induced peripheral neuropathy; TICN, taxane-induced central neurotoxicity; TIN, taxane-induced neurotoxicity; TIPN, taxane-induced peripheral neuropathy; TLR4, toll-like receptor-4; TRPA1, transient receptor potential cation channel subfamily A member 1; TRPV1, transient receptor potential cation channel subfamily V member 1; TRPV4, transient receptor potential cation channel subfamily V member 4.

In this study we analyzed the systemic antiallodynic properties of diacerhein, a drug used to treat osteoarthritis, in inflammatory and neuropathic models of nociception in mice. The effects of diacerhein were compared with those of gabapentin, a drug used clinically for the management of neuropathic pain. Similar to gabapentin, diacerhein was able to significantly reverse the mechanical allodynia induced by carrageenan. A significant inhibition of carrageenan-induced nociception was also observed when diacerhein was administered by the intrathecal but not by the intraplantar route. The treatment with diacerhein or with gabapentin also inhibited the mechanical allodynia induced by complete Freund's adjuvant (CFA) or after the partial ligation of the sciatic nerve (PLSN). In the same range of doses, diacerhein or gabapentin did not affect the locomotor activity, motor coordination, or body temperature of the animals. The present results indicate that diacerhein produces marked antiallodynic effects in carrageenan and CFA nociception models and also inhibits the neuropathic pain after PLSN, with an efficacy similar to that observed for gabapentin. Diacerhein may be a potentially interesting tool for the management of inflammatory and neuropathic pain.